In its broadest sense, this unity or cooperation
may refer to a worldwide religious unity; by
the advocation of a greater sense of shared spirituality across the
three Abrahamic faiths
of Judaism,
Christianity
and Islam.
Most commonly, however, ecumenism is used in a more narrow meaning;
referring to a greater cooperation among different religious
denominations of a single one of these faiths.

Christian ecumenism and interfaith pluralism

Christian
ecumenism, in the narrower sense referred to above, is the
promotion of unity or cooperation between distinct religious groups
or denominations of Christianity. For some Catholics it may, but
not always, have the goal of reconciling all who profess Christian
faith to bring them into a single, visible organization, i.e.
through union with the Roman
Catholic Church. For some Protestants spiritual unity
suffices.

According to Edmund
Schlink,most important in Christian ecumenism is that people
focus primarily on Christ, not on separate church organizations. In
his book Ökumenische Dogmatik (1983), he says Christians who see
the risen Christ at work in the lives of various Christians and in
diverse churches, realize that the unity of Christ's church has
never been lost (pages 694-700; also his "Report," Dialog 1963,
2:4, 328), but has instead been distorted and obscured by different
historical experiences and by spiritual myopia. Both are overcome
in renewed faith in Christ. Included in that is responding to his
admonition (John 17; also Philippians 2) to be one in him and love
one another as a witness to the world. The result of mutual
recognition would be a discernible worldwide fellowship, organized
in a historically new way (pages 707-708; also Skibbe, A Quiet
Reformer 1999, 122-4; Schlink, The Vision of the Pope 2001).

Christian ecumenism is distinguished from
interfaith
pluralism. Ecumenism in this broad sense is called religious
pluralism, as distinguished from ecumenism within a faith movement.
Standing against ecumenism is the traditional Orthodox Church which
staunchly maintains there is but one church, the historic Orthodox
church. Leading the anti ecumenical movement in the 1980s was Fr.
John Boylan of the OCA. The interfaith movement strives
for greater mutual respect, toleration, and co-operation among the
world
religions.

Ecumenism as interfaith dialogue between
representatives of diverse faiths, does not necessarily intend
reconciling their adherents into full, organic
unity with one another but simply to promote better relations.
It promotes toleration, mutual respect and cooperation, whether
among Christian denominations, or between Christianity and other
faiths.

Three approaches to Christian unity

For a significant part
of the Christian world, the highest aim of the Christian faith is
the reconciliation of all humanity into a full and conscious union
as one Christian Church, visibly united with mutual accountability
between the parts and the whole. The desire is expressed by many
denominations of Christendom,
that all who profess faith in Christ in sincerity, would be more
fully cooperative and supportive of one another.

Christian ecumenism can be described in terms of
the three largest divisions of Christianity: Roman Catholic,
Eastern Orthodox, and Protestant. While this underemphasizes the
complexity of these divisions, it is a useful model.

Roman Catholicism

Like the Eastern
Orthodox Church, the Roman
Catholic Church has always considered it a duty of the highest
rank to seek full unity with estranged communions of
fellow-Christians, and at the same time to reject what it saw as
promiscuous and false union that would mean being unfaithful to or
glossing over the teaching of Sacred Scripture and Tradition.

Before the Second
Vatican Council, the main stress was laid on this second
aspect, as exemplified in canon 1258 of the 1917 Code of Canon Law:

It is illicit for the faithful to assist at or participate in
any way in non-Catholic religious functions.

For a serious reason requiring, in case of doubt, the Bishop's
approval, passive or merely material presence at non-Catholic
funerals, weddings and similar occasions because of holding a civil
office or as a courtesy can be tolerated, provided there is no
danger of perversion or scandal.

The 1983
Code of Canon Law has no corresponding canon. It absolutely
forbids Catholic priests to concelebrate the Eucharist with members
of communities not in full communion with the Catholic Church
(canon 908), but allows, in certain circumstances and under certain
conditions, other sharing in the sacraments. And the Directory for
the Application of Principles and Norms on Ecumenism, 102 states:
"Christians may be encouraged to share in spiritual activities and
resources, i.e., to share that spiritual heritage they have in
common in a manner and to a degree appropriate to their present
divided state."

Pope John
XXIII, who convoked the Council that brought this change of
emphasis about, said that the Council's aim was to seek renewal of
the Church itself, which would serve, for those separated from the
See of Rome, as a "gentle invitation to seek and find that unity
for which Jesus Christ prayed so ardently to his heavenly
Father."

Every renewal of the Church
is essentially grounded in an increase of fidelity to her own
calling. Undoubtedly this is the basis of the movement toward unity
... There can be no ecumenism worthy of the name without a change
of heart. For it is from renewal of the inner life of our minds,
from self-denial and an unstinted love that desires of unity take
their rise and develop in a mature way. We should therefore pray to
the Holy Spirit for the grace to be genuinely self-denying, humble.
gentle in the service of others, and to have an attitude of
brotherly generosity towards them. ... The words of St. John hold
good about sins against unity: "If we say we have not sinned, we
make him a liar, and his word is not in us". So we humbly beg
pardon of God and of our separated brethren, just as we forgive
them that trespass against us.}}

While some Eastern Orthodox
Churches commonly baptize converts from the Catholic Church,
thereby refusing to recognize the baptism that the converts have
previously received, the Catholic Church has always accepted the
validity of all the sacraments administered by the Eastern Orthodox
and Oriental Orthodox Churches.

The Catholic Church likewise
has never applied the terms "heterodox" or "heretic" to the Eastern
Orthodox Church or its members. Even the term "schism", as defined
in canon 751 of its Code of Canon Law ("the withdrawal of
submission to the Supreme Pontiff or from communion with the
members of the Church subject to him"), does not, strictly
speaking, apply to the situation of the concrete individual members
of the Eastern Orthodox Church today as viewed by the Catholic
Church.

Eastern Orthodoxy

The Oriental
Orthodox and Eastern
Orthodox churches each consider themselves to be the original
church, from which the West was divided in the fifth and eleventh
centuries, respectively. Several of these churches have in recent
years engaged in theological dialogue with each other and with some
of the Western churches, though short of full communion. The
Eastern Orthodox have participated in the Interfaith movement, with
students active in the
World Student Christian Federation since the late 19th century
and some Orthodox patriarchs enlisting their communions as charter
members of the
World Council of Churches. Nevertheless, the Orthodox have not
been willing to participate in any redefinition of the Christian
faith toward a reduced, minimal, anti-dogmatic and anti-traditional
Christianity. Christianity for the Eastern Orthodox is the Church;
and the Church is Orthodoxy—nothing less and nothing
else. Therefore, while Orthodox ecumenism is "open to dialogue with
the devil himself", the Orthodox have defined their position in the
ecumenical movement as being "witnesses to the truth", the goal
being to reconcile the heterodox (i.e., non-Orthodox)
back into Orthodoxy.

One way to observe the
attitude of the Orthodox Church towards non-Orthodox is to see how
they receive new members from other faiths. Non-Christians, such as
Buddhists or atheists, who wish to become Orthodox Christians are
accepted through the sacraments of baptism and chrismation. Protestants and
Roman Catholics are sometimes received through chrismation only,
provided they had received a trinitarian
baptism. Also Protestants and Roman Catholics are often referred to
as "heterodox", which simply means "other believing", rather than
as heretics, implying
that they did not willfully reject the Church. However, such
policies are decided by each individual church, and more
traditional groups will receive all converts only by baptism and
chrismation.

There has always been a
segment within the Orthodox Church that is wary of ecumenical
involvement, and in recent years greater restraint has been shown
by leaders within the various national churches. Any work to
embrace estranged communions must strenously guard against a
promiscuous and false union with them. There is at present no
official intercommunion between Orthodox and non-Orthodox
churches.